Many in Japan were angry at the couple, who said they had forced their son out of the car to teach him a lesson after he had thrown stone at cars and people.

They had originally told police that he got lost while on a family outing, but later admitted they lied because they feared social censure.

The case sparked debate in Japan about discipline, with some voices calling for understanding of parental frustration in making their kids behave, though most condemned the extent to which the boy's mother and father acted.

And though some have called for them to be prosecuted, police said that they will not face charges, a local officer said Tuesday.

"We plan not to regard it as a criminal case," a Hokkaido police spokesman told AFP, indicating it would be referred to social services.

Japan lost boy's father gives statement about his 'excessive behaviour'

01:18

Toru Numata, a lawyer who handles abuse and domestic violence cases, told AFP: "Considering the factors behind the case, the chances of making it a prosecutable one are extremely slim."

Numata said that the focus is likely to shift to the boy's mental care, and on possible trauma from the ordeal.

After Yamato left the hospital, people took to social media to celebrate his recovery, with one person tweeting: "Good he was safe... Please give him lots of love."

But some expressed fatigue with the heated press coverage.

"Do media need to chase him this much?," a user tweeted. "It'd be better to leave him alone."

Rescue workers and soldiers spent days scouring the mountainous forest - where bears are known to roam - after Yamato went missing 10 days ago.

He was finally discovered on Friday by a soldier, sheltering in a hut on a military drill field around five kilometres (three miles) from where he was abandoned.

The boy was suffering from mild dehydration and was sent to the hospital.

Police questioned him for about an hour in hospital on Monday accompanied by his mother and doctors, the Tokyo Shimbun reported.

He was quoted by the daily as telling police: "I walked alone and met no one", adding that he sometimes stopped to rest and arrived at the hut in the dark.

Yamato kept himself warm there in the chilly northern nights by sleeping between two mattresses and drank water from an outside tap, though had nothing solid to eat.

After being found he was lauded on social media for his endurance, with some even suggesting the survival skills he exhibited could make him a future candidate for Japan's military.

His father, 44-year-old Takayuki Tanooka, said in comments broadcast Monday that he apologised to his son and that the boy had forgiven him.